This invention relates to an improved carrier for installing a repair liner at the location of a damaged or leaking portion of conduit, typically a gravity flow sewer line or a service line. When an underground pipe leaks or is damaged, it is extremely expensive to excavate and externally repair or replace a segment of the pipe line. In many situations, the pipe line can be internally repaired at a great savings in cost and time.
The improved point repair sleeve carrier of this invention is designed to transport a repair liner wrapped around a bladder portion of the carrier to the point of repair, wherein the bladder is inflated and the liner in the form of a circumferential sleeve is pressed against the wall of the conduit.
Techniques in repairing larger concrete pipe with a cementicious composition, by packing ejected composition against the inside wall of the pipe at the location to be repaired using an inflatable bladder device, have been applied to repairs using a repair liner. The repair liner is typically a durable fabric material, such as a carbon or polyester fiberglass composite, impregnated with a thermo-setting polymer resin that cures in place. The sleeve carrier is similar to a repair packer and has an expandable bladder for forcing the repair material against the inner wall of a conduit. The resin impregnated liner is wrapped around an elongated expandable bladder as a sleeve. Since the sleeve must conform to the inner wall of the pipe that has a larger diameter than the deflated carrier bladder, the liner must be folded or overlapped when installed on the bladder. The expanded sleeve must also be released from the carrier bladder when the bladder is deflated and the carrier withdrawn from the pipe. When cured, the liner forms a structural repair that in many instances is stronger than the original conduit.
Various methods have been devised to retain the liner on the carrier to minimize dislodging the liner when the carrier is drawn through the pipe to the location of the repair. In Walsh et al., U.S. Pat. No. 6,019,136, issued Feb. 1, 2000, an improved system is described for attaching a liner to an inflatable carrier using Velcro® straps to minimize dislocation of the liner. Other methods, such as the use of disposable twist ties, may be used to secure the liner to the carrier. The liner is wrapped as a sleeve on the carrier bladder and is nevertheless subject to dislodgment by contact of the leading edge of the sleeve with the walls of the pipe, particularly when encountering joints or laterals.
In addition to methods for temporarily securing a liner to the carrier to prevent dislocation of the liner, improvements to the design of the carrier can also minimize the potential for dislodging the liner during installation.
Adding a guide flange or wheeled carriage to at least the lead end of the carrier elevates the carrier end and reduces snagging of the lead edge of the wrapped liner sleeve. Attempts to stiffen the elongated carrier reduce the ability of the carrier to flex or bend when attempting to insert the carrier into a horizontal pipe through a vertical manhole have been problematic. The carrier frequently must be inserted through a vertical manhole into a horizontal pipe and therefore requires that the carrier be flexible during initial installation.
The improved point repair sleeve carrier 10 of this invention solves many of the problems and difficulties in installing a releasable liner wrapped on an expandable bladder of a supporting carrier.